Holding-down device for shears, punches, presses, &amp;c.



K. 0. GARDNER & P. G. BIGGERT, JR. HOLDING DOWN DEVICE FOR SHEARS,PUNGHES PRESSBS, 6w.

APPLIOATIQN FILED D2018, 1909, 980,241 Patented Jan. 3. 1911.

3 SHEETS-SHEET 1.

K. 0. GARDNER & F. G. BIGGERT, J11. HOLDING 1 ow11v DEVICE ron sums,PUNOHBS, PRESSES, m.

Patented Jan. 3, 1911.

APPLICATION FILED DEC-18, 1909.

3 SHEETS-SHEET 3.

q iairsg 1 m WM Ww y UNITED STATES PATENT OFFICE.

KIRTLAND C. GARDNER AND FLORENCE C. BIGGER'I, JR., OF PITTSBURG,PENNSYL- VANIA, ASSIGNORS TO UNITED ENGINEERING 8c FOUNDRY COMPANY, OFPITTS- BURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

HOLDING-DOWN DEVICE FOR SHEARS, PUNCHES, PRESSES, 8w.

To all whom it may concern:

Be it known that we, KIRTLAND C. GARD- NER and FLORENCE C. BIGGERT, J11,both of Pittsburg, Allegheny county, Pennsylvania, have invented a newand useful Holding- Down Device for Shears, Punches, Presses, &c., ofwhich the following is a full, clear, and exact description, referencebeing had to the accompanying drawings, forming part of thisspecification, in which-- Figure 1 is a front elevation, partly brokenaway, of a portion of a shearing machine having our invention appliedthereto; Fig. 2 is a section on the line II-II of Fig. 1; Fig. 3 is afront elevation partly in vertical section of a portion of the machine;Fig. 4 is a detail view showing the shoe member in vertical section; andFig. 5

. is a side view showing the bracket by which the parts embodying ourimprovement are attached to the machine.

Our invention has relation to the class of metal shears, presses,punches, etc, and is designed to provide a work holding-down attachmenttherefor of simple, novel and efficient character.

The precise nature of our invention will be best understood by referenceto the ac companying drawings in which we have shown the preferredembodiment thereof, and which will now be described, it beingpremised,however, that various changes may be made in the details ofconstruction and arrangement of the parts without departing from thespirit and scope of our invention as set forth in the appended claims.

In the drawings, in which we have shown the invention applied to ashear, the numeral 2 designates the frame of the shear, 3 the uppermovable shear blade mounted in the reciprocating head or carrier 4., and5 is the lower stationary shear blade secured to the shear block oranvil 6. 7 designates the actuating crank for the head or carrier 4:,and which is driven through the gearing 8. The shears shown are ingeneral of wellknown type, and need not be specifically described, ourinvention being independent of the shears proper and relating solely tothe holding-down attachment therefor, and which is capable ofapplication to various types of shears, and also to punches, presses,etc.

The invention comprises a transversely Specification of Letters Patent.

Application filed December 18, 1909. Serial No. 533,918.

Patented Jan. 3, 1911.

arranged holding-down shoe or foot 9 placed transversely above the shearblock or anvil 6 and adapted to engage the upper side of the work piece.This shoe or foot is somewhat loosely connected to a piston 10 by meansof the cross-bars 11 and springs 12 and by the link 13. This link hasthe ball portion 14 at each end, one of these portions having a seat inthe upper face of the block, while the other end bears in the concaveseat in the upper portion of the piston, which is made hollow to receivethe link. The piston extends upwardly through a stuffing box 15 into acylinder 16. The space 17 within the cylinder above the upper end of thepiston is designed to be filled with oil or other suitable fluid. Thisspace is connected by the passage 18, and the two ports 19 and 20 with achamber 21. The port 19 is controlled by an upwardly seating valve 22,which is normally held away from its seat by the action of a spring 23;and the port 20 is normally closed by a downwardly seating valve 24;held to its seat by a spring 25, the two springs 23 and 25 beingarranged in the chamber 21. The chamber 21 is provided with a suitablefilling aperture closed by a removable screw plug 26, or by othersuitable means, this aperture also permitting access to the valves. Theshoe 9 is provided with the upwardly extending side portions 9, whichare connected at their upper ends by the transverse portion 9. The sideportions 9 are provided with the lateral guiding tongues or flanges 9,which work in guides 9 secured to the reciprocating head of the shear. 9is a bracket which is also rigidly secured to the reciprocating head andwhich is provided with the lugs 9, which are engaged by overhanging lugs9 at the upper portion of the side members 9 of the shoe 9, theengagement of the lugs 9 with the lugs 9 serving to normally hold theshoe raised when the shear is opened.

The operation is as follows: The parts being in the position shown inFigs. 1, 2 and 3, the downward stroke of the shear head or carrier tbrings the shoe 9 into engagement with the work and further downwardmovement of the head or carrier causes the piston or plunger to beforced upwardly into the cylinder against the pressure of the fluidtherein. This pressure opens the valve 24 and a portion of the fluidescapes through the port 20 into the chamber 21. On the reverse strokeof the head 4, the parts are carried upwardly therewith until the shoeor carrier comes in contact with the fixed transverse stop or knock downbar 27, which prevents its further upward movement, the cylinder slidingupwardly on the piston during the remaining portion of the up-stroke ofthe head. This releases the pressure which has been holding the valve 22seated and the spring 25 opens said valve and permits fluid from thechamber 21 to flow back into the passage 18 and cylinder space 17. Thestop or knockdown bar 27, however, only comes into action as a means ofreturning the cylinder to its original position after the shear has madea cut, in case the plunger works so stiff in the cylinder as to cause itto rise with the cylinder. If the piston or plunger works freely in thecylinder, it will remain in its lowered position until the lugs 9contact with the lugs 9 as before described.

The loose connection between the foot or shoe 9 and the piston enablesthe shoe to adjust itself on the lower ball end of the link 13 so as toseat squarely upon the work piece notwithstanding irregularitiesthereof. The device described forms a very simple, convenient andeflicient attachment for the purpose, which can be readily applied toexisting shears.

It will be obvious that various changes may be made in the details ofconstruction and arrangement with the several parts. Thus, the shoe orfoot may be differently attached; changes may be made in the arrangementof the piston and cylinder; and changes may also be made in thearrangement of the chamber or reservoir 21 and of the ports and valveswhich control the connections between the same and the interior of thecylinder.

The application of the invention to other types of metal workingmachines, such as punches and presses, will be apparent to those skilledin the art.

What we claim is 1. The combination with a metal working machine havinga reciprocating head or carrier, of a work-holding device mounted on thehead or carrier and comprising a holding-down member, a plungerconnected thereto, a cylinder within which the plunger works, a liquidchamber having two ports leading into the cylinder, and oppositelyacting check valves controlling said ports, substantially as described.

2. The combination with a metal working machine having a reciprocatinghead or carrier, of a work-holding device mounted on the head or carrierand comprising a holding-down member, a plunger connected thereto, acylinder within which the plunger works, a liquid chamber having twoports. leading into the cylinder, and oppositely acting check valvescontrolling said ports, said holding-down member having upwardextensions and a stop or knock-clown bar for contact therewith,substantially as described.

8. The combination with a metal working machine having a reciprocatinghead or carrier, of a work-holding device mounted on the head or carrierand comprising a holding-down member, a plunger connected thereto, acylinder within which the plunger works, a liquid chamber having twoports leading into the cylinder, and oppositely acting check valvescontrolling said ports,

the cylinder space above the plunger, the chamber, and the connectingports forming a closed system adapted to be filled with liquid,substantially as described.

4. The combination with a metal working machine having a reciprocatinghead or carrier, of a work-holding device mounted on the head or carrierand comprising a holdingdown member, a plunger connected thereto, acylinder within which the plunger works, a liquid chamber having twoports leading into the cylinder, and oppositely acting check valvescontrolling said ports, together with means for permitting and guidingthe independent vertical movement of the holding-downmember,'substantially as described.

In testimony whereof, we have hereunto set our hands.

KIRTLAND C. GARDNER. FLORENCE G. BIGGERT, JR.

Witnesses ALICE A. TRILL, EDWARD R. HAzLnWooD.

